Method of inhibiting the transmission of AIDS virus

ABSTRACT

An inexpensive, easily available and convenient method of inhibiting the transmission of the AIDS virus in humans as a result of sexual intercourse is provided. The method relies upon a dual mode of action of antiviral compositions comprising silver salts, such as silver sulfadiazine, alone or in combination with chlorhexidine or sodium deoxycholate. These composition are effective to reduce the infectivity of the AIDS virus and also kill the causative organisms of many other sexually transmitted diseases (STD). The method of the invention is therefore useful to reduce the immediate risk of AIDS transmission. It also reduces future risk of AIDS transmission by eliminating STD causing organisms which increase the risk of AIDS.

BACKGROUND OF THE INVENTION

This application is a continuation-in-part of prior U.S. patentapplication Ser. No. 018,624, filed Feb. 25, 1987 and abandoned upon thefiling of this application.

BACKGROUND OF THE INVENTION

The present invention relates to a method of inhibiting the transmissionof Acquired Immunodeficiency Syndrome (AIDS).

AIDS is a fatal catastrophic disease that presently infects millions ofpeople worldwide. Although initially concentrated in central Africa andin certain high risk groups in other geographic areas including theUnited States, AIDS is now spreading to other areas and is appearing inindividuals who are not members of the recognized risk groups. As aresult, major efforts are being made to develop methods of preventingthe transmission of AIDS, methods of curing AIDS once contracted, andmethods of ameliorating the symptoms of AIDS. To date, however, AIDS hasproven difficult to treat or prevent.

AIDS is caused by a virus. This virus has been referred to by a numberof names in the literature, including HIV (human immunodeficiency virus)LAV (lymphadenopathy-associated virus), ARV (AIDS-related virus) andHTLV-III (human T-cell leukemia virus-III). For simplicity, the viruscausing AIDS will be referred to herein as the AIDS virus.

It is generally known that viruses can be divided into two groups basedupon the nature of the virus' genetic material. Some viruses are DNAviruses, that is there genetic material is deoxyribonucleic acid, whileothers are RNA (ribonucleic acid) viruses. The RNA viruses can furtherbe divided into two groups, those in which replication of the viralgenome proceeds by making an RNA copy directly from the RNA genome andthose in which a DNA intermediate is involved. This latter type of RNAvirus is called a retrovirus.

The AIDS virus is a retrovirus Thus, like other retroviruses, it has anenzyme called reverse transcriptase (or RNA-dependent DNA polymerase)which catalyzes transcription of viral RNA into double helical DNA. ThisDNA sequence is integrated into the genome of the infected cell where itis known as a provirus. Subsequent transcription of this provirus by thetranscription mechanism of the infected cell produces new viral RNA forpackaging into new virus particles.

Because the AIDS virus may lie dormant in an infected cell in the formof a provirus for extended periods of time, it has been difficult toestablish the precise routes by which AIDS is spread. It is known,however, that AIDS can be transmitted to a person by transfusing thatperson with blood containing the AIDS virus. AIDS can also betransmitted to a person through homosexual or heterosexual intercoursewith a partner infected with the AIDS virus. Transmission of the AIDSvirus is facilitated by preexisting sexually transmitted diseases(STD's) other than AIDS, for example gonorrhea. Further, scientistssuspect that the AIDS virus is spread easily during sexual intercoursedue to tearing of tissue which would abet entry of the AIDS virus intothe blood stream.

In response to the growing threat of AIDS transmission, the use ofcondoms during sexual intercourse has been suggested as a means ofpreventing transmission of the AIDS virus. Improper use of condoms, ortheir perforation during intercourse renders them only partiallyeffective. Accordingly, there is a pressing need for a better method ofinhibiting the transmission of the AIDS virus in humans during sexualintercourse and during surgical procedures on infected patients. It isan object of the present invention to provide such a method.

SUMMARY OF THE INVENTION

The present invention provides an inexpensive, easily available andconvenient method of inhibiting the transmission of the AIDS virus inhumans as a result of sexual intercourse. The method relies upon a dualmode of action of particular compounds and combinations thereof whichresults in a rapid killing action within minutes. These compounds areeffective to reduce the infectivity of the AIDS virus and also kill thecausative organisms of many other STD's after short exposure. The methodof the invention is therefore useful to reduce the immediate risk ofAIDS transmission. It also reduces future risk of AIDS transmission byeliminating STD causing organisms which increase the risk of AIDS.

Central to the method of the invention is the discovery that silversalts, such as silver sulfadiazine (AgSD), are effective antiviralagents against retroviruses including the AIDS virus. Such materials hadpreviously been recognized as antibacterial agents useful in treatingburns in man and animal. C.L. Fox, Jr., U.S. Pat. No. 3,761,590. AgSDhas also been shown to be effective against certain viruses such asherpes simplex and herpes zoster and against the causative organisms ofmany STD's including Candida albicans, Treponema pallidum and gonorrhea.U.S. Pat. No. 4,415,565 of Wysor shows further antiviral activity ofAgSD against certain RNA viruses, but none of these are retroviruses.Thus, while AgSD is a well studied material, there was no basis toexpect that it would have activity against the AIDS retrovirus which hasproven so difficult to inhibit or destroy.

We have also found that combinations of silver compounds such as AgSDwith other antibacterial agents lead to an unexpected enhancement of theantiviral activity of AgSD and also in a rapid killing action.Specifically, AgSD in combination with chlorhexidine, a broad spectrumantibacterial, is substantially more effective for reducing theinfectivity of the AIDS virus than AgSD alone, despite the fact thechlorhexidine alone has no effect on infectivity of AIDS virus under thesame conditions. Increased effectiveness was also noted for combinationsof AgSD with detergents such as deoxycholate.

In view of these findings, the invention contemplates a method ofinhibiting the transmission of AIDS in humans upon sexual intercoursecomprising topically applying an effective antiviral amount of a silversalt such as silver sulfadiazine, alone or in combination with otheragents such as chlorhexidine or deoxycholate, to a sexual canal of ahuman prior to or during sexual intercourse. This application can becarried out by introducing a cream or foam into the sexual canal, or bycoating the inhibitory composition onto a condom or other device that isinserted into the sexual canal.

BRIEF DESCRIPTION OF THE FIGURE

FIG. 1 is a graph of the rate of incorporation of radiolabeled thymidineby hepatitis B virus following exposure of the virus to AgSD alone or incombination with other agents.

DETAILED DESCRIPTION OF THE INVENTION

As noted above, the method of the present invention of inhibiting thetransmission of AIDS virus in humans upon sexual intercourse comprisestopically applying an effective antiviral amount of an antiviralcomposition comprising a silver salt, alone or in combination with otheractive ingredients, to a sexual canal of a human prior to or duringsexual intercourse. As used in this application, the term sexual canalrefers to either a vaginal or an anal canal.

The antiviral composition used in the method of the invention comprisesa silver salt. While the examples hereinbelow use one specific silversalt, AgSD, other silver salts may also be used. Other suitable silversalts include silver acetate, silver benzoate, silver carbonate, silverchloride, silver iodate, silver iodide, silver lactate, silver laurate,silver nitrate, silver oxide, silver palmitate, and silver salts ofproteins.

The antiviral composition used in the method of the invention preferablyalso comprises one or more additional ingredients which enhance theantiviral effectiveness of the silver salt. Thus, the antiviralcomposition may contain a biguanidine such as chlorhexidine, ordetergents such as deoxycholate or benzalkonium chloride. Suitable saltsof each of these materials may also be used.

The antiviral composition may also include other materials which areeffective against STD-causing organisms which will reduce the long termrisk of AIDS infection. Examples of such materials include nonoxynol,which is effective against gonococcus and quinolones which are effectiveagainst numerous STD-causing organisms. It should be noted thatchlorhexidine and the detergents noted above are also effective againsta variety of STD-causing organisms, including herpes simplex virus (HSV)and Candida albicans.

The antiviral compositions for use in the invention can be applied as(a) a dispersion in a water-dispersible hydrophilic carrier; (b) as adispersion in a substantially water insoluble carrier; (c) as adispersion in a semi-soft or cream-like water-dispersible orwater-soluble oil-in-water emulsion carrier; of (d) as a dispersion inan aqueous sucrose carrier, e.g. an approximately 25%-50% by weightaqueous sucrose solution Specific examples of formulating silversulfadiazine in various carriers are provided in U.S. Pat. No. 3,761,590which is incorporated herein by reference. The carrier will preferablycontain from about 0.1 to about 10% by weight of the silver salt and upto 2% of other active agents

The antiviral composition useful in the method of the invention can becontained in a squeezable tube having an applicator nozzle. Thisfacilitates topical application of the composition to the sexual canalprior to intercourse by inserting the nozzle into the sexual canal andsqueezing the tube to force the antiviral composition into the sexualcanal. Alternatively, the antiviral can be applied with any of variousknown applicators for delivering drugs into a sexual canal. Theantiviral composition can also be topically applied during sexualintercourse by coating the penis itself or coating a condom with alubricant material, such as K-Y Jelly (Johnson & Johnson), that containsthe silver salt.

The antiviral composition of the invention may also be introduced intothe sexual canal as a coating on a device intended for insertion in thesexual canal. Examples of such devices include condoms, medical gloves,and diaphragms. Such devices may be coated or impregnated with theantiviral composition by spraying the completed device or byincorporating the antiviral composition during manufacture. Specifictechniques for preparing the devices are described in U.S. patentapplication Ser. No 154,920, filed Feb. 11, 1988, and itscombination-in-part filed Oct. 14, 1988, both of which are incorporatedherein by reference.

The experimental results which demonstrate the effectiveness of theclaimed method are set forth below. These tests involve the AIDS virusor a recognized model system for the AIDS virus. Further, although thetests with the AIDS virus itself are necessarily in vitro tests in viewof the catastrophic consequences of AIDS, these in vitro tests arehighly predictive of and correlate with in vivo efficacy. They thussupport the surprising finding that compositions containing silver saltscan be used to inhibit transmission of AIDS as a result of sexualintercourse.

EXAMPLE 1

The effectiveness of AgSD against the AIDS virus in vitro was assessedby testing the infectivity of samples of HTLV-III in H9 cells afterexposure to AgSD for 10 minutes. Due to the relatively low titersachievable with the AIDS virus, it was necessary to devise means forseparating the bulk of the AgSD from the virus to be assayed. After anumber of preliminary experiments, it was found that the best method ofthose investigated was to rapidly pass the AgSD/AIDS virus mixture overa Sephadex G-25M column, recover the AIDS virus containing void volumeand precipitate the virus using polyethylene glycol (PEG).

To determine recovery of the virus using this method, a controlpreparation containing virus but no AgSD was similarly processed.

It was also necessary to confirm that this procedure was effective toremove all of the AgSD. This was accomplished using "Stop Controls".This involved processing AgSD alone through the column, precipitatingthe same fraction with PEG and then adding active AIDS virus to theprecipitate. If the titer of the stop control had been similar to thecontrol preparation containing virus but no AgSD it would have indicatedthat little or no AgSD was present in the precipitate. In fact, however,the titer was substantially lower in the stop controls (Samples 4 and 6)than in the corresponding test samples without silver sulfadiazine(Samples 1 and 2). This indicates that some of the silver sulfadiazineis not being separated. While this means that virus killing occurredover a longer period than the ten minute contact time, it also suggeststhat the virucidal activity is fairly strong to persist even at thereduced levels.

The specific tests conducted are summarized in Table 1. For each sampleto which virus was added initially, the virus sample was a stocksolution prepared from a 10,000 fold concentrate of HTLV-III obtainedfrom Bionetics Research. This material was diluted 1:10 with ConditionedInfection Medium (CIM) to form a stock solution with an actual virustiter of 10⁵.5 /ml. Two AgSD stock preparations were also prepared, a 1%by weight in 50% by weight aqueous sucrose preparation and an 0.5% byweight in 25% by weight aqueous sucrose preparation.

To conduct the tests, 60 μl aliquots of the virus stock were placed inmicrofuge tubes as samples 1-3 and 6 as indicated in Table 1. This wasmixed with 540 μl of the respective AgSD preparations in tubes 3 and 5and with 540 μl of CIM in tubes 1 and 2. Tubes 4 and 6 each received 600μl of the respective AgSD preparations, but no virus. Each tube was thenmixed with a vortex mixer and allowed to incubate for 10 minutes at roomtemperature.

To separate the AgSD from the virus, the contents of each tubecontaining AgSD then centrifuged in a microfuge for 1 minute, and thesupernatants were collected. These supernatants and the entire sample oftube 2 were then introduced onto a Sephadex-25M column. The columns usedhad a fitted disc at the top of the column and a void volume ofapproximately 1 ml. These columns are normally stored in sodium azideand had been prepared by washing under sterile conditions with 18successive 4 ml portions of CIM medium on the day prior to theexperiment.

Each of the samples was placed on the column until it passed through thefitted disc. The column was then eluted with 4 ml of CIM medium. Thefirst 3 ml of eluent was discarded and the last ml was collected into asterile microfuge tube containing 0.35 ml of 30% PEG 6000 in phosphatebuffer. These tubes were held at 0° C. for at least 30 minutes and thencentrifuged for 1 minute in a microfuge. The pellets were collected andresuspended in either 0.5 ml CIM (samples 2, 3 and 5) or in an HTLV-IIIcontaining medium made by diluting 0.7 parts of the virus stock with 6.3parts of CIM.

Each of the six samples thus prepared was assayed in quadruplicate with10-fold dilutions in CIM for its ability to infect H9 cells. This wasdone by adding 50 μl of a preparation containing 2.4×10⁶ /ml H9 cellsthat had been conditioned in CIM for 1 hour at 37° C. to each 100 μl ofsample or dilution. This culture was fed 25 μl of CIM on days 4, 7 and10. On day 4, cytotoxicity was evaluated by visual examination of thecultures.

The results of these observations are shown in Table 1. As can beclearly seen, AgSD substantially reduced the infectivity of AIDS virustested without any observation of cytotoxicity.

EXAMPLE 2

The effect of AgSD, chlorhexidine and sodium deoxycholate, bothindividually and in combination, on the infectivity of the ARV-2 strainof AIDS virus was tested in H9 cells using lower concentrations of drugsuch as can be practically coated onto a glove or condom or otherdevice. These concentrations were below the level that producedsubstantial observable cytotoxicity, even during incubation with thevirus, and yet were effective at killing the virus.

A stock solution of virus containing 3 to 5 ×10⁴ infectious virusparticles/ml was preincubated with the various drugs as indicated inTable 2 for 15 minutes. The virus sample was then diluted 4-fold inorder to reduce the concentrations of the drugs below levels toxic to H9cells (see Example 3 below) and mixed with 250,000 H9 cells in a totalvolume of 1 ml. After 24 hours, the cells were assayed to determine thepercentage of the culture expressing viral antigen. This time intervalwas selected as it allows for only a single round of viral infection tohave occurred such that the number of cells infected was a directreflection of the number of infectious virions present in the originalsample.

As can be seen from Table 2, AgSD alone at these low concentrations wasonly slightly effective, but better results were obtained when AgSD wasused in combination with either sodium deoxycholate and chlorhexidine.Of particular significance is the marked reduction in infectivityobserved for the combination of AgSD (5 μl ml) and chlorhexidine (5 μlml) since chlorhexidine (10 μml) did not itself reduce viralinfectivity.

EXAMPLE 3

The toxicity of the various agents used in the antiviral compositions ofthe invention to human T⁴ -lymphocytes (H9 cells) and macrophages whichare the carriers of the AIDS virus may be relevant to the effectivenessof a drug. This is because killing these cells when present in semen orvaginal fluids may lead to release of virus making it more susceptibleto the effects of the drug. With this in mind, the effect of shortexposure (10 minutes) of AgSD and other drugs on H9 cells was tested bytreating a suspension of H9 cells (1.6×10⁶ /ml in HBSS) with 50 and 100μl/ml of each drug or drug combination. After incubating for 10 minutes,the cells were washed twice in thirty volumes of HBSS; resuspended inRPMI 10% FCS+NaPyruvate and plated into 24 well plates at 4×10⁵cells/ml. Cell viability was determined after 24 hours and is reportedas numbers of viable cells per ml and viable percentage (live cells/livecells+dead cells) in Table 3 A. As can be seen, each of the agentstested kills some of the cells, although the most significant killing isobserved for 100 μl/ml AgSD and the combination of AgSD and sodiumdeoxycholate.

The effectiveness of killing of macrophages was also tested as shown inTable 3B. In the experiment, peritonial normal mouse macrophages wereenriched by attaching to petri dishes and adjusted to a cellconcentration of 5 to 10×10⁶ /ml 0.1 ml aliquots of this suspension wereplated in microtiter plates and 10μ and 5μ of each of four samples wasadded. The control plate received PBS only. After 20 minutes ofincubation in a CO₂ incubator, the cells were tested for viability usingtryphan-blue dye. The percent kill is shown in Table 3B.

EXAMPLE 4

In vivo tests were performed using Rauscher Leukemia Virus (RLV), arecognized retrovirus model (see, e.g., Nature 323, 467-469 (1986);Rupecht et al., Proc. Nat'l. Acad. Sci. USA 82, 7733-7737 (1985)) whichis used by the FDA in testing drugs for use in treating AIDS. RLV wasintroduced into Balb/CICR mice in which it infects the spleen. The levelof virus infectivity was quantified by determining the weight increaseof the mouse spleen after 20 days from infection.

A preliminary experiment was first carried out to determine the effectof the drugs to be tested on the spleen. Nine sets of five mice each (6week old female mice) received 0.25 ml injections into the tail vein ofone of an extract of a glove treated with one of the followingsolutions:

1. Silver Sulfadiazine (2%)

2. Sodium Deoxycholate (2%)

3 Chlorhexidine (2%)

4. Silver Sulfadiazine (1%)+Sodium Deoxycholate (1%)

5. Silver Sulfadiazine (1%)+Chlorhexidine (1%)

6. Fusidic Acid (2%)

7. Fusidic Acid (1%)+Chlorhexidine (1%)

8. Saline incubated glove

9. Saline-no glove

Each treatment was prepared by incubating 1.5 ml Dulbecco's PhosphateBuffered Saline (PBS) for 10 minutes at 37° C. in the finger tip of alatex glove. After incubation, as much as possible of the material wasremoved from the glove. 0.4 ml of PBS was then introduced into the gloveand this was the sample which was introduced into the animals. Theanimals that did not receive a clean stick during the injection wereexcluded from the study. Thus two of the groups only had four animalseach that were considered.

Eight days after injection each of the animals was sacrificed and thespleen weights determined for each animal. No increase in spleen weightwas observed in any of the groups.

An additional eleven groups of 5 mice each were then used to test theeffectiveness of these same compounds against infectivity of RLV. Eachtreatment was prepared by incubating 0.4 ml sterile PBS containing RVB3(a strain of RLV) for 10 minutes in a glove tip which had previously hadone of drugs or straight PBS incubated in it as described above. Threeadditional controls, a PBS containing glove with no virus, a virussample not incubated in a glove, and a PBS sample not incubated in aglove were also run. The mice in this case were sacrificed 20 days afterinjection and spleen weights determined as shown in Table 4. Each of thematerials tested showed a substantial reduction in virus infectivity.

EXAMPLE 5

The combination of AgSD with chlorhexidine and deoxycholate was alsofound to be particularly effective against several STD-causingorganisms. As shown in Tables 5A and 5B silver sulfadiazine incombination with chlorhexidine or sodium deoxycholate is particularlyeffective against Candida albicans. Similarly, these combinations areeffective to kill Gonococcus (Table 6) and herpes virus (Tables 7A and7B).

EXAMPLE 6

The effect of AgSD alone or in combination with chlorhexidine or sodiumdeoxycholate on DNA synthesis by Hepatitis B Virus was studied bymeasuring the rate of incorporation of radiolabeled thymidine. As aresult, it was found that the AgSD interferes with the RNA-dependent DNApolymerase of Hepatitis B virus, an interference which is enhanced byusing it in combination with either chlorhexidine or sodium deoxycholate(FIG. 1).

                                      TABLE 1                                     __________________________________________________________________________    ASSAY MIXTURES AND RESULTS                                                                 HTLV-III                 PEG Pellet                                                                            Log.sub.10 **                   Sample       (Stock 21)                                                                          Mixture            Resuspended                                                                           TCID.sub.50                                                                         Log***                    No.  Material                                                                              10-1  CIM   AgSD                                                                              Stop Procedure                                                                         in (0.5 ml)                                                                           Per/ml                                                                              Kill                                                                              Cytotoxicity          __________________________________________________________________________    1    HTLV-III                                                                              60 ul 540 ul                                                                              --  --       --      4.5   --  0                          (Stock 21)                                                                    (10-.sup.1                                                               2    HTLV-III                                                                              "     "     --  Column + Peg                                                                           CIM     4.25  --  0                          (Stock 21)                                                                    (10-.sup.1                                                               3    1% AgSD "     --    540 Cent.* + Peg                                                                           CIM     2.0   2.25                                                                              0                          in 50%                                                                        aqueous                                                                       sucrose                                                                       solution                                                                 4    1% AgSD --          600 Cent.* + Peg                                                                           10.sup.-2 HTLV-III                                                                    3.25  --  0                          in 50%                           (Stop Control)                               aqueous                                                                       sucrose                                                                       solution                                                                 5    0.5% AgSD                                                                             60 ul --    540 Cent.* + Peg                                                                           CIM     2.25  2.0 0                          in 25%                                                                        aqueous                                                                       solution                                                                 6    0.5% AgSD                                                                             --          600 Cent.* + Peg                                                                           10.sup.-2 HTLV-III                                                                    3.75  --  0                          in 25%                           (Stop Control)                               aqueous                                                                       solution                                                                 __________________________________________________________________________     *Centrifuge 1 minute in microfuge  place supernatant on column                **TCID.sub.50 = Tissue Culture Infecting Dose.sub.50                          ***Compared to Sample No. 2                                              

                  TABLE 2                                                         ______________________________________                                        Drug During     Final       %      % Infection                                Incubation                                                                             (μg/ml)                                                                           (Drug) μg/ml                                                                           Infection                                                                            v. Control                                 ______________________________________                                        chlorhexidine                                                                          10     2.5         3.35   108                                        (CHA)                                                                         sodium   40     10.0        3.35   108                                        deoxycholate                                                                  (NaDC)                                                                        AgSD     10     2.5         2.95    95                                        AgSD +   10     2.5+        2.85    92                                        NaDC     40     10.0                                                          AgSD +   5+     1.25 +      2.45    72                                        CHA      5      1.25                                                          ______________________________________                                    

                  TABLE 3A                                                        ______________________________________                                               Viable                                                                        Cells/ml                % Viab**                                       ______________________________________                                        *AgSD                                                                          50        4 × 10.sup.5                                                                   Cells in terrible condition.                                                                   37                                         100        5 × 10.sup.4                                                                   "                 0                                         CHA                                                                            50      1.5 × 10.sup.6      73                                         100      2.5 × 10.sup.5                                                                   "                20                                         NaDC                                                                           50      1.2 × 10.sup.6      73                                         100      2.0 × 10.sup.6      44                                         AgSD 50 +                                                                              1.5 × 10.sup.4       0                                         CHA 50                                                                        H.sub.2 O                                                                              3.1 × 10.sup.6      89                                         Cells Alone                                                                            3.0 × 10.sup.6      88                                         ______________________________________                                         *AgSD → insoluble. In an attempt to remove drug cells were spun at     200 g for 15 sec. (including acceleteration and deceleration time)            → Cells pipetted off, then washed two times.                           ##STR1##                                                                 

                  TABLE 3B                                                        ______________________________________                                        Results                                                                       Rate of Killing of Macrophage by Drugs                                                           % Kill                                                     ______________________________________                                        Control               36                                                      AgSD (100 μg)     100                                                      CHA (100 μg)      100                                                      AgSD + CHA (50 μg + 50 μg)                                                                    85                                                      ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        Results                                                                                              Weight of  Weight                                                Concentration of                                                                           Spleen (mg)                                                                              Increase                                              Drug in Coating                                                                            (Average of                                                                              from                                        Drug in Glove                                                                           Solution (%) 6 Animals) Control (mg)                                ______________________________________                                        Silver sulfadia-                                                                        2            106        20                                          zine                                                                          Deoxycholate                                                                            2            109        23                                          Chlorhexidine                                                                           2            234        148                                         Silver sulfadia-                                                                        1 + 1        115        29                                          zine + deoxycholate                                                           Silver sulfadia-                                                                        1 + 1        103        17                                          zine + chlorhexidine                                                          Fusidic acid                                                                            2            107        21                                          Fusidic acid +                                                                          1 +`1        319        23                                          Chlorhexidine                                                                 Control glove +         86         0                                          PBS medium                                                                    No glove - only         86         0                                          PBS medium                                                                    Control glove +        1,627      1,541                                       RVB3                                                                          No glove +             1,280      1,194                                       RVB3                                                                          ______________________________________                                    

                  TABLE 5A                                                        ______________________________________                                        Rate of Killing of Candida-albicans                                           by silver sulfadiazine an other                                               agents on short exposure                                                                              Colony Counts in Culture                              Drug        Concentration                                                                             (10 Minute Incubation)                                ______________________________________                                        Silver sulfadiazine                                                                       100         10,000                                                Chlorhexidine                                                                             100            30                                                 Deoxycholate                                                                              1,000         8,000                                               AgSD + Chlorhex-                                                                          50 + 50        0                                                  idine                                                                         AgSD + Deoxycho-                                                                          100 + 100      20                                                 late                                                                          Nonoxynol    0.2%       >50,000                                               Control                 >50,000                                               ______________________________________                                         3 ml of Saboraud broth containing 10.sup.5 organisms of Candida albicans      were incubated with the above drugs. Aliquots were removed at 5 and 10        minutes and were subcultured.                                            

                  TABLE 5B                                                        ______________________________________                                        Antibacterial Efficacy of Drug Coated Gloves                                  against Candida albicans                                                      ______________________________________                                        Treated glove fingers were draped over the top of culture tubes with the      treated side forming the inside of the cup shape. The 3.0 ml of TBS           containing 10.sup.3 organisms of Candida albicans was dispensed in each       finger and all placed in the water bath shaker at 37° C. Samples       were removed at 15 minutes, 1 hour, 2 hours, and 4 hours. They were           diluted 1-10 and plated on blood agar in 2.0 ml amounts.                      ______________________________________                                                  Colony Counts in Culture                                            Drug in Glove                                                                             15 Minutes                                                                              1 Hour  2 Hours                                                                              4 Hours                                  ______________________________________                                        None (Control)                                                                            1,400     2,000   4,000  6,000                                    Chlorhexidine                                                                               75         0    0      0                                        Silver Sulfadiazine                                                                       1,650     1,500   1,500  2,200                                    Silver Sulfadiazine                                                                          0         0    0      0                                        + Chlorhexidine                                                               Silver Sulfadiazine                                                                       1,500       400   0      0                                        + Deoxycholate                                                                Silver Sulfadiazine                                                                          0         0    0      0                                        +  Chlorhexidine                                                              + Nonoxynol                                                                   ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        Killing of Gonococcus by                                                      Silver Sulfadiazine and Other Agents                                                           Colony Counts in Culture                                     Drugs      μg/ml    5 Minutes 10 Minutes                                   ______________________________________                                        AgSD       100          4,000     2,000                                       Deoxycholate                                                                             1,000       12,000     4,000                                       Chlorhexidine                                                                            100          2,000      10                                         Nonoxynol   0.1%         40        70                                         AgSD +     50 + 50        0         0                                         Chlorhexidine                                                                 AgSD +       100 + 1,000                                                                               10         0                                         Deoxycholate                                                                  None (Control)         >50,000   >50,000                                      ______________________________________                                         Drugs were suspended in 5 ml of cultures containing 105 organisms of          gonococcus and incubated. Aliquots were removed at 5 and 10 minute            intervals and subcultured for colony counts.                             

                  TABLE 7A                                                        ______________________________________                                        Toxicity of Drugs for HSV                                                     One ml HSV at 3 × 106/ml was incubated with 200 μliters of drugs     each 500 μg/ml stock solution. After 20 minutes at R.T., the virus was     titered on monolayers of vero cells, incubated for 2 hours, then              overlayed with methyl cellulose. Virus titers were read after 48 hours.       No drug toxicity* was seen in rows titer read in.                             ______________________________________                                        μliters added to l ml Virus                                                                 Titer    % Inhibition                                        ______________________________________                                        200 AgSD         5.2 × 10.sup.5                                                                   81                                                  200 Chlorhexidine                                                                              2.7 × 10.sup.6                                                                   0                                                   100 AgSD +       1.5 × 10.sup.4                                                                   99.5                                                100 Chlorhexidine                                                             200 NaDC         3.2 × 10.sup.6                                                                   0                                                   100 NaDC × 100 AgSD                                                                      1.3 × 10.sup.6                                                                   54                                                  100 NaDC ×   8 × 10.sup.4                                                                   93                                                  100 Chlorhexidine                                                             200 Benzalkonium choloride                                                                     5.2 × 10.sup.4                                                                   98                                                  200 H.sub.2 O    2.8 × 10.sup.6                                                                   0                                                   200 Media        3.3 × 10.sup.6                                                                   0                                                   ______________________________________                                         *Drug conc. in first row was 4-8μg/ml                                 

                  TABLE 7B                                                        ______________________________________                                        Effect on HSV-1 of Interaction with Drug Treated Gloves                       HSV-1 was diluted to 3 × 10.sup.6 PFU/ml in DME 10% FCS. One ml of      virus was placed in sterile drug treated gloves, incubated for 10 min. at     room temperature then titered on Vero cells.                                  ______________________________________                                        Treatment        Titer (PFU/ml)                                               ______________________________________                                        virus (no glove) 2.9 × 10.sup.6                                         virus + control tube                                                                           3.0 × 10.sup.6                                         virus + tube w   4.3 × 10.sup.6                                         virus + tube x   <10                                                          virus + tube y   <10                                                          ______________________________________                                         W = Silver sulfadiazine                                                       X = Silver sulfadiazine + Deoxycholate                                        Y = Silver sulfadiazine + Chlorhexidine                                  

We claim:
 1. A method of inhibiting the transmission of AIDS virus inhumans comprising topically applying an effective antiviral amount of anenhanced antiviral composition comprising an antiviral silver salt andan antiviral biquanide to a sexual canal of a human, wherein the silversalt and the biquanide are present in amounts such that the compositionis effective to inhibit transmission of AIDS in humans.
 2. A methodaccording to claim 1, wherein the silver salt is selected from the groupconsisting of silver sulfadiazine, silver acetate, silver benzoate,silver carbonate, silver chloride, silver iodate, silver iodide, silverlactate, silver laurate, silver nitrate, silver oxide, silver palmitate,and silver salts of proteins.
 3. A method according to claim 1, whereinthe silver salt is silver sulfadiazine.
 4. A method according to claim2, wherein the biguanidine is chlorhexidine or a pharmaceuticallyacceptable salt thereof.
 5. A method according to claim 2, wherein theantiviral composition further comprises an effective amount of adetergent.
 6. A method according to claim 5, wherein the detergent issodium deoxycholate.
 7. A method according to claim 1, wherein theantiviral composition is a dispersion in a water-dispersible hydrophiliccarrier.
 8. A method according to claim 1, wherein the antiviralcomposition is a dispersion in a semi-soft or cream-like,water-dispersible or water-soluble oil-in-water emulsion carrier.
 9. Amethod according to claim 1, wherein the antiviral composition is adispersion in an aqueous sucrose solution.
 10. A method according to anyone of claims 1 to 3 and 4, 7, wherein the antiviral compositioncomprises from 0.1 to 10 percent by weight of the silver salt.
 11. Amethod according to claim 1, wherein the antiviral composition isapplied as a component of a lubricant material coating a penis.
 12. Amethod according to claim 1, wherein the antiviral composition isapplied as a component of a lubricant material applied to a condom. 13.A method according to claim 1, wherein the antiviral composition isapplied as a coating to a device intended for insertion in a sexualcanal.
 14. A method according to claim 1, wherein the antiviralcomposition is applied as a component of an impregnant in a deviceintended for insertion in a sexual canal.